1. Field of the Invention
The present invention relates to navigating in a geographic information system.
2. Related Art
A geographic information system (GIS) is a system for archiving, retrieving, displaying and/or manipulating data indexed according to the data elements' geographic coordinates. The data element may be a variety of data types such as, for example, imagery, maps, models of buildings and terrain and other geographic features.
A geographic information system may display geographic information to a user from a perspective of a virtual camera. The perspective of a virtual camera may be defined by a position and orientation. By changing the position and orientation of the virtual camera, the user can sightsee within geographic information. For example, the user may “visit” the Eiffel Tower in the GIS by directing a perspective of a virtual camera toward a representation of the Eiffel Tower.
A perspective of a virtual camera may be stored in a language such as Keyhole Markup Language (KML). Interpreting the KML, a GIS may move the virtual camera to a stored perspective to display a sight. Using the stored perspective, a user can return to the sight. Further, KML can store a sequence of perspectives. Interpreting the KML, the GIS may move the virtual camera iteratively from one perspective to the next. This enables the user to view a series of sights, e.g., the Eiffel Tower, Big Ben, etc. However, this approach may only provide a limited user experience.
Methods and systems are needed for sightseeing in a geographic information that provide a more satisfying user experience.